Black Scabbardfish

Distribution: Only UK/Irish populations are found in and around the Rockall Trough to the west of Ireland.

Feeds on: Fish and squid

Description: Elongated, eel-like body. Dorsal fin runs entire length of the body, as does lateral line. Tail fin is very small and deeply forked. Head and snout is relatively large, as is the mouth which is full of sharp, fang-like teeth and a protruding lower jaw. Eyes are also very large. No pelvic fins are present. Colour is generally a dark metallic black.

The black scabbardfish is a deep-water predator that is seldom encountered by any type of rod and line anglers, due to the immense depth at which it lives. Adult black scabbardfish generally live at depths of several thousand metres, but may make vertical migrations to depths of several hundred metres under the cover of darkness.

Distribution

They are generally found to the west British Isles, especially in the very deep waters of the Rockall Trough to the west of Ireland. Elsewhere in the world they are found in deep-waters off the coast of France and Spain and further northwards around Iceland and Greenland. They are also found in the middle of the Atlantic around the Portuguese island of Madeira, and in limited numbers off the coasts of America and Canada.

Diet, Behaviour and Reproduction

The large mouth full of sharp teeth make it clear that this species is a predator, although not a great deal is known about their feeding habits. It is thought that black scabbardfish spend daylight hours on or around the seabed where they are mostly inactive, and then swim up to mid-water during darkness and feed by hunting pelagic fish such as mackerel, herring, as well as taking squid, cuttlefish and prawns. Black scabbardfish reproduce once they are aged five to eight years. Again little is known about the spawning patterns of this species, but it is thought that there are several distinct sub-populations of this species, at least some of which spawn in and around the deep waters off the west coast of Britain.

Commercial Value

Left: Black scabbardfish on sale in a supermarket in Madeira. Right: the dish of Espada com banana which consists of deep fried black scabbardfish and with fried bananas on top. It is considered a delicacy in Portugal.

Black scabbardfish are edible and have commercial value. Although there would be few takers for this species in a British fishmongers or supermarket counter there is a demand for this species in France and Spain, and in Madeira the black scabbardfish is seen as a delicacy. Fishermen working out of Madeira use specialised deep-water longlines to catch black scabbard fish, while trawlers fishing in the deep waters to the west of the British Isles occasionally catch this species as bycatch. There has been little research into black scabbardfish stocks, although the government agency Cefas (Centre for Environment, Fisheries and Aquaculture Science) states that due to the fact that they mature fairly late and live in a delicate deep-water environment the black scabbardfish is only able to sustain limited commercial exploitation. The International Union for the Conservation of Nature classes this species as one of Least Concern.